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November, 2015:

Chaotic Motion Device Aims for Scalability, Portability

The world is full of “chaotic motion,” in other words, continuous but non-uniform types of physical excitation that are nevertheless pervasive and commonplace. Ocean waves are a naturally occurring example. So is the movement of people as they walk or run in everyday life. What almost all have in common is that they represent a nearly limitless source of energy if only a means could be found to convert them into a reliable form of electric power generation.

Methods of doing so have long been a focus of engineering research. A UK-based company has come up with something different: a single type of device that could be scaled to provide useful, usable power from a few watts to hundreds of kilowatts depending on the scale of the motion source.


The company is WITT Energy based in Plymouth in South West England and founded by a husband and wife team, Martin and Mairi Wickett. Their aim was to find a means of converting bi-directional movement to rotation. Their initial idea has now been embodied into the design for a device that goes by the name Whatever Input to Torsion Transfer (WITT). It is claimed to be one of the first ever practicable pieces of equipment with the potential to translate multiple degrees of motion – up, down, backwards, forwards and rotation about an axis – into a single output able to drive a generator to produce electricity. (Watch a video of the generator in action.)

The basic principle involves the use of pendulums that react to external movement. These drive a flywheel and gearbox that in turn drive a conventional generator. The potential benefits could be considerable.

The first is its potential scalability from a wearable device to something that could be mounted in a boat to exploit its pitching and rolling motions. Second, all of the essential working parts can be sealed inside a housing pierced only by the wires carrying the electric current, thereby making it resilient to damage from external forces. Another is that it could be able to produce power across a wide range of excitation – a marine device, for example, should continue to operate in storm conditions. It also would be flexible in operation and could be used to charge batteries if there was no immediate need for power or if the source of motion was intermittent.

The company’s commercial director Nicholas Gill says that the device has already won at least one award for innovation – the 2013 Gulfstream Navigator Award worth $100,000 made by the Ocean Exchange organization, an international venture that seeks to recognize environmentally friendly innovation with a potential for global application. He says the device is also attracting interest from the German conglomerate Schaeffler, which Gill says has agreed to work with WITT to help refine the concept. Both the Indian and U.S. defense departments also have expressed interest, he says.

The defense departments’ interest has been stimulated in part by the device’s potential to be built into a soldier’s backpack. Gill says this would enable the device to provide a means of constantly recharging the batteries used to power electronic equipment that military personnel now carry. He says that a WITT device weighing two pounds and capable of generating 10W of power could feasibly be developed and would be sufficient to meet military applications.

A prototype of such a device has been tested and, Gill says, has achieved a “peak power” output of 5W. Further lightweighting of almost all its component parts could help boost power output towards that target figure. Moreover, Gill says that the company could exploit the need for the pendulums to retain some weight by making them incorporate batteries, which would contribute “net zero weight” to the device.

That possible application is likely to be beaten into real use by a larger version of the concept that is capable of generating as much as 200W. WITT Energy is developing that device in cooperation with UK precision engineering operation Gibbs Gears. Gill says that this device is intended for marine use although the company has also recognized that fixed floating objects such as marker buoys present a potential market. A prototype is scheduled to appear by “the third quarter of 2016” with a market launch possibly in 2017, he says.

Gill says that by late 2015 the company will launch a crowdsourcing push that aims to bring in at least $1.1-4.5 million.

Give us a clearer picture, Hong Kong lawmakers urge officials on electricity market study findings

Results described as failing to show a diversity of opinions

Lawmakers are demanding a more precise breakdown of the results of a public consultation on the development of the electricity market as nearly a third of submissions were templates and the rest a mystery.

They said the results of the government’s consultation were simplistic and failed to show a diversity of opinions.

“The results of this consultation, I think, is too simple,” said tourism sector lawmaker Yiu Si-wing at a meeting of the Legislative Council’s economic development panel on Monday.

“There are 5,000 templates but we don’t have any breakdown of these other figures. We need to know people’s views and what most of the public is concerned about. Some may have put forward very unique and professional views … such as on renewable energy.”

Panel chairman James Tien Pei-chun agreed, and asked the bureau to provide more detailed analysis. “We want to know the justifications. There are over 10,000 submissions so there must very different views,” he said.

Deputy secretary for the environment Vincent Liu Ming-kwong said his office would consider if more detailed information could be provided to members.

The findings of the government’s consultation, which drew 15,765 submissions, saw no need to break the monopolies held by the city’s two power suppliers, nor cut the profits they could make.

More than half of respondents favoured keeping return rates at 9.99 per cent to give power companies an incentive to invest.

A third of submissions to the consultation, which ended in June, came at the behest of green groups, which favoured lower fees and more competition. The source of the rest remained a mystery.

Others favoured lower returns but “a relatively small number of respondents” suggested a rate below 6 per cent”. Earlier this year, the government had proposed lowering the rate of return from the 9.99 per cent down to 6 to 8 per cent.

Some lawmakers, including those from the business sector, had reservations on whether the level was appropriate without stricter conditions imposed on the suppliers for more renewable energy generation and the interconnection of their power grids. They also were sceptical about renewing the framework for another 10 or 15 years.

Labour’s Lee Cheuk-yan said the government claimed large-scale renewable energy was not feasible locally but that technology was improving. “If we sign for another 10 years and your grid isn’t opened, no one will be able to tap into it,” he said.

Tien, from the pro-business Liberal Party, said even 6 to 8 per cent was “a bit high” given the economic and low-interest rate environment. “When I joined Legco in 1988, the permitted rate of return was 15 per cent, but no one thought it was high because borrowing costs and inflation were both more than 10 per cent,” he said.

“The yield on 30-year US treasury bonds is now at 3 per cent … so the 6 to 8 per cent really amounts to big earnings for them in this environment.”

He also pointed out that there was no need for such a high guaranteed return or lengthy contract – both CLP Power and HK Electric are eyeing another 15 years – as the two suppliers had already made most of the long-term investments they needed over the last few decades.

In response, Liu said many coal-fired plants would soon have to be retired and replaced, while natural gas generation would involve high costs. “Many new investments are needed,” he said.

Environment chief Wong Kam-sing said while public opinion was clear, its consultant would examine the rate of return and the government would begin official negotiations with the two suppliers next year with the aim of setting a final rate in the next one or two.

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As Paris climate conference nears, Hong Kong’s environment chief confident on emissions blueprint

As global conference in Paris approaches, Wong Kam-sing points to city’s blueprint for reaching peak emissions by around 2020

Hong Kong may not be directly involved with state-to-state climate negotiations but Wong Kam-sing, the environment secretary, is heading into next month’s United Nations Conference of the Parties (COP21) in Paris with a degree of confidence.

He said Hong Kong’s total emissions will peak around 2020, when a shake-up in how the city gets its electric power is slated for completion and a cluster of coal-fired plants are retired to make way for relatively cleaner gas-fired ones – roughly a decade earlier than the mainland’s pledge to peak emissions around 2030.

By “around 2020″, Hong Kong will be on track to reduce its carbon intensity – emissions per unit of GDP – by 50 to 60 per cent and energy intensity by up to 40 per cent. By that year, it will have already met its 2010 target of reducing total emissions by 19 to 33 per cent from 2005 levels, he said.

“The road forward is clear but we won’t see immediate reductions daily or even annually. It’s not necessary,” Wong said. “We are nearing peak emissions. It will happen when the coal-fired power plants are retired and when we are using cleaner fuel for electricity generation.”

He was quick to list a basket of measures under his energy-saving blueprint that would help achieve the intensity targets, including cutting energy use in government buildings further and tightening the buildings energy code.

“By 2025, this [tightened code] will help Hong Kong save 5 billion kilowatt-hours of electricity and 3.5 million tonnes of carbon,” he said.

But the latest government data showed that the city’s greenhouse-gas emissions have been rising since 2000, amounting to some 43 million tonnes of carbon dioxide equivalent in 2012. More than two-thirds of it still comes from electricity generation.

The first coal-fired plant to have been built since the 1980s will be retired only in 2017 and the rest are scheduled to be completely retired by the early 2030s.

Hanging in the balance will also be negotiations with the city’s two power companies on the electricity-supply regulatory framework after 2018.

Wong will brief the legislature’s development panel on the latest results of the public consultation on the future electricity market today and will discuss market readiness and future changes to the regulatory regime with the two suppliers before January.

Greenpeace had calculated that under a “business as usual” approach”, only 31 per cent of emissions could be cut in the next two decades.

It called on the government to stop nuclear imports when the contract with the Daya Bay nuclear plant comes to an end in 2034 and to boost renewables in the fuel mix.

Greenpeace senior campaigner Frances Yeung Hoi-shan said the government needed more aggressive schemes to cut emissions given the city’s high per capita annual generation.

Cheung Chi-wah, WWF Hong Kong’s senior head for climate, said the government urgently needed a climate plan that would go beyond 2020.

Wong said the government would keep an “open attitude” on the nuclear question post-2034, but any post-2020 climate and energy policy would need further discussion.

“Our current targets only go up to 2020. As to how we can set longer-term goals, we will have to come back to Hong Kong [from Paris] and discuss this with the community on how we can undertake this process.”

Hong Kong will arrive at the Paris climate talks empty handed; let’s make sure it leaves with bold ideas to cut the city’s rising emissions

Gavin Edwards says the UN meeting in Paris offers an ideal opportunity for our environment secretary to learn about, and adopt, other cities’ pioneering efforts

Hong Kong’s Environment Secretary Wong Kam-sing will travel to Paris at the end of this month for the UN climate negotiations, where world governments will come together to agree a bold new set of targets and actions on climate change. The key outcome will hopefully be a new international agreement on the climate, applicable to all countries, with the aim of keeping global warming below 2 degrees Celsius. In preparation for the meeting, more than 150 countries have already indicated a number of pledges they may be willing to make – their Intended Nationally Determined Contributions – that can form part of the agreement. For example, the European Union pledges to cut its emissions by 40 per cent (from 1990 levels) by 2030, Costa Rica is aiming to be carbon neutral by 2021, and China aims to lower its carbon intensity by 60 to 65 per cent by 2030 (from 2005) and ensure its emissions peak by 2030.

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As we approach the final weeks in the lead-up to the Paris agreement, a couple of challenges are emerging – one global, one local. The global challenge is that the intended contributions by all countries have been modelled by climate scientists and policy experts at Climate Action Tracker (an independent group of four leading research organisations), and they forecast that the world will see a 2.7 degree rise by late in the century if the Paris agreement succeeds and is implemented.

This falls well short of the 2 degree target governments are aiming for, and is a long way shy of the generally accepted safe temperature rise which our planet can tolerate: 1.5 degrees. And this is not just some academic numbers game. At 2.7 degrees warmer, we could experience significant food shortages globally as crops fail in sub-Saharan Africa, and our own major source of food – the Pearl River Delta – experiences increasing flooding. Even a 2 degree rise – the stated aim of the Paris agreement – spells the end of the world’s coral reefs and a whole host of other impacts driven by increasingly extreme weather patterns.

At 2.7 degrees warmer, we could experience significant food shortages globally as crops fail in sub-Saharan Africa

Second, the local challenge: Hong Kong’s contribution to averting catastrophic climate change. Wong gathered key government, corporate and NGO representatives together on November 6 to launch the Hong Kong Climate Change Report, outlining government efforts. However, instead of articulating a plan of action for the decades ahead, he summarised existing policies and efforts, and is taking a wait-and-see approach to the Paris climate negotiation so the government can then consider its next steps. This is odd, given that China (which reports and commits globally on its greenhouse gas emissions, including those of Hong Kong) has outlined its plan well beyond 2020. On a recent trip to the US, President Xi Jinping (習近平) articulated a range of measures, including greenhouse-gas emissions targets, investments in renewable energy, a national emission trading scheme to regulate large carbon dioxide emitters, and clear targets for green buildings.

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Here in Hong Kong, the current plan is to reduce carbon dioxide emissions by 19 to 33 per cent by 2020 (from 2005), but that’s all. With current efforts, we’ll only achieve the low end of this target, and only if the long-promised initiative to reduce the burning of coal for electricity generation is implemented. Contrast this with cities around the world which will come together at a special event during the Paris negotiations, share their ambitious plans, and learn from each other. Greater Taipei will cut its emissions by 20 per cent by 2026 (from 2006), Yokohama will cut by 80 per cent by 2050 (from 2005), London by 60 per cent by 2025 (from 1990) and New York by 40 per cent by 2030 (from 1990). However, Hong Kong’s greenhouse gas emissions have been steadily rising over the past decade, by 23 per cent from 2002 to 2012.

The development of renewable energy in the city has barely begun. And CLP Power is proposing new gas-fired power generation instead of using renewable energy. The social cost of fossil fuel has never been mentioned, even in the latest document of the electricity market regulatory regime review. If our electricity market is not going to change, there is no chance for us to stop climate change. Under the Air Pollution Control Ordinance, carbon dioxide is not even considered a pollutant, even though it is widely agreed that ever-escalating carbon dioxide emissions are one of the largest threats to our planet and our city. Our electricity market is not ready to tackle climate change.

So, if the past decade was something of a lost decade for Hong Kong in terms of making a meaningful and commensurate contribution to tackling climate change, what should we do in the next decade, to catch up?

If our electricity market is not going to change, there is no chance for us to stop climate change

First, the Environment Bureau has a huge opportunity to address the lack of renewable energy development by adopting a comprehensive feed-in tariff policy to reward anyone who installs solar panels on rooftops or wind turbines in coastal waters. As the government wraps up its review of the Scheme of Control Agreement which governs our electricity production, it must include a renewable energy support policy, even if we are one of the last cities in Asia to adopt such a policy.

Second, it’s time for our private sector to put funding into renewable energy and energy efficiency development. Globally, there are more new investments in renewable energies such as wind and solar than there are in coal, gas and nuclear combined. They are effectively winning against these dirty energy sources, because governments around the world realise the importance of supporting safe, low-carbon energy. Some US$270 billion is being invested in low carbon development.

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So instead of supporting CLP’s pitch to build another gas plant, the government should encourage future investment in renewables, and greater investment in energy efficiency. For example, a simple scheme to encourage all grocery and convenience shops to put doors on their display fridges will cut their fridge energy consumption by 50 per cent, according to recent WWF research.

Lastly, we need a plan for Hong Kong that goes beyond 2020. Our environment secretary arrives in Paris empty-handed without a longer-term plan while other cities profile theirs. However, it does not have to be a wasted journey – he will have an incredible opportunity to learn about the pioneering efforts of other cities, and to bring back ideas to adapt to Hong Kong. This can start with a plan to substantially cut our city’s emissions by 2030, and a plan to adopt a new scheme of control to encourage renewable energy development.

The difference between a world that is 2.7 degrees warmer and one that is only 1.5 degrees warmer is the difference between a liveable planet and a planet that is thrown into chaos. It’s time for Hong Kong to step up its efforts by leaving Paris with new ideas and bolder pledges to do much more. And when Hong Kong attends the next big climate conference in a few years’ time, I very much hope that these efforts will earn us international recognition as Asia’s sustainable city.

Gavin Edwards is conservation director at WWF-Hong Kong

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Clear Solar Panels Could Offer Energetic Window Retrofit

Engineers from Michigan State University (MSU) are designing transparent solar panels that could be retrofit to existing glass-covered buildings to generate electric power.

Traditional opaque solar panels such as silicon soak up much of the sun’s light, including visible light, and convert it to energy. A transparent panel allows visible light to shine through and making light that is invisible to the human eye—such as ultraviolet and infrared—do the work.

By making the solar panels transparent, MSU materials scientist and chemical engineer Richard Lunt and his team are creating the potential for them to cover existing windows.

However, making the panels clear is a challenge. So the team came up with ways to layer patterns onto the cell in a way that makes them uniformly transparent. The transparent solar cell under development incorporates thin coatings of organic and inorganic nanostructure materials that selectively harvest the parts of the solar radiation spectrum that are not visible to the eye.

“We actually used a variety of different stencils to pattern our devices,” Lunt says. Each active material has its own pattern. After every layer, the researchers put down a new stencil and in this way build complex structures, he adds.

Team member Margaret Young is testing whether the same process can be used on thin plastic.

“This is much lighter and much more flexible, so instead of rebuilding windows, we could just put this over an existing window,” she says.

Lunt says that he expects that in the next 20 years, this type of technology will be deployed extensively—turning cities and landscapes into solar harvesting systems, surfaces and solar farms without the aesthetic issues that today’s opaque solar panels create.

Could wind drones be the next evolution in wind power generation?

Drones will eventually be “as ubiquitous as pigeons,” London-based futurist Liam Young recently predicted. They are omnipresent already. Only five years ago drones belonged to the realm of the military, unaffordable for anyone else. Today, they are for hobbyists and even kids. Drones arrived in our lives and conquered the extreme ends of the market for technical goods. They proved to provide the best value for both, defense budgets and pocket money. Now the race is on to fill the gap in the middle: startups, corporates and analysts try to find the most promising commercial applications for drones. That is quite a challenge since drones can be used for a surprising variety of tasks. Much media attention was paid to Amazons’, Google’s and DHL’s announcement of using delivery drones. Others see the future for drones in surveillance, detecting fires, cracks in pipelines or illegal wood logging. They can also monitor farmland in detail for precision farming. Autonomous solar powered drones can also be used to hover at high altitude over an area for months to provide wireless communication similar to a satellite. Facebook and Google have invested in startup companies in this field. But there are other disruptive uses for drone technology which the current debate is largely unaware of.

One example is Elon Musk and his SpaceX company. He is working at landing and later reusing Falcon rockets after they have delivered their payload into space. It is impossible for a pilot to control a precision upright landing of a rocket that literally falls out of the sky. Only cutting-edge drone technology can do the job. If the rocket was to be recycled it would lower the flight costs from the cost of building a rocket to the cost of refueling it. That is $200,000 instead of $55 million.1 The business potential for the “rocket drone” would be enormous.

Or take Miles Loyd. In the energy crises of the late 1970s Miles Loyd worked as an engineer at Lawrence Livermore National Laboratory. He attempted to build the best wind generator imaginable.

He had the radical idea of building it without a tower, only using a flying wing connected to the ground by a tether, much like a kite. He calculated the expected energy output of his “flying wind generator”. Based on the formula he first established – today known as Loyd’s Formula – he found that a wing with the size, weight and aerodynamics of a standard plane wing of the 1970s could produce 6.7 MW of power. Even larger wings with an output of 45 MW seemed feasible. To put this into perspective: even today, 35 years later, the average wind turbine is still below 3 MW and the largest existing prototype has 8 MW. Loyd obtained a patent2 and published an article3 on this new technology.

And here the story ends. He could not convince investors to finance his flying wind generator, because he had no solution for one problem: how to control the flying wing without a pilot? Today, we have a technology that lets us control flying objects without a pilot. It is called: drones. If we can apply this new technology to Loyd’s old formula we can build a new type of drone: the wind drone.


How exactly does a wind drone work? There is a great resemblance to kite surfers. Kite surfers use a kite and a tether to pull a surfer through the water. The same mechanism can be used to generate electricity. The tethered kite or wing is connected to a drum and a generator on the ground and the tether is wound around the drum. The wing tears at the tether and turns the drum to generate electricity. Once the tether is fully unwound, the wing nosedives and the tether is quickly reeled in. Then the cycle starts again. This up-and-down motion inspired the name “yo-yo” type wind drone (%%0815-IF-Drone-1%%).

Google X, overseen by Sergey Brin, is working on a different wind drone in its Makani4 project. Google’s approach is to use little propellers (mini wind turbines) and generators directly mounted on the wing where they produce electricity. An electric cable is woven into the tether and transfers the electricity to the ground. In 2013 Makani presented a working prototype. They already built their first scaled up product with 600 kW output and announced that it will fly in 2015.

Google will be the first team to show a wind drone with power outputs comparable to today’s wind turbines. But they are not the only ones who have realized that drone technology is ripe to take on Loyd’s formula. Companies including 3M, ABB, Alstom, E.ON, Honeywell, Statkraft and Softbank have conducted research on wind drones and/or financed one of the dozens of airborne wind energy startups worldwide. Some of the prototypes use soft wings resembling a surf kite or a paraglider, others use hard wings like the wing of an airplane. The designs also differ in many other details. A dominant design has not yet emerged. But irrespective of their final design, wind drones share three characteristics that could turn them into the killer application for drone technology: they will disrupt their market, they will be one of the first autonomous drone applications to be market ready and they will have the largest market of all drone applications.


Producing wind energy is not a new idea and we already have a tried and trusted device for this task: the wind turbine. Wind drones will have to offer significant advantages over wind turbines to conquer this market. Airborne wind energy companies claim that wind drones can be built at half the price of wind turbines. In addition, they claim that downtimes for wind drones will be significantly lower and wind drones therefore produce twice as much energy with the same rated power. According to their calculations energy from wind drones could therefore be available at just one quarter of the price of energy produced by wind turbines. But are such claims realistic?


Can you manufacture wind drones more cheaply than wind turbines? The capital costs of a wind turbine which make up the bulk of the total costs of wind energy are the following (see %%0815-IF-Drone-2%%).5
The structural elements, the tower, the blades, the foundation and the rotor hub make up half of the total capital costs of wind turbines. Material requirements are extremely high: Up to 700 tons of steel for the tower,6 another 100 tons of steel for the rotor hub,7 up to 100 tons of glass-fiber reinforced plastic for the blades,8 and up to 4,000 tons of concrete for the foundation.

Wind drones lack theses massive structures. The tower is replaced by a thin tether. A wind drone with the power of the largest existing wind turbine (8 MW) requires a tether that is 2.5 inches/6 cm thick and would weigh less than one ton.9 Only minimal foundations are required and the wings can be much lighter requiring only 1 to 10 percent of the material of the blades of a wind turbine.10 The Google Makani 600 kW wing weighs below 2 tons including the tether and generators on board.11 A comparable 600 kW wind turbine weighs between 50 and 100 tons without foundation.

The required components for power generation are cheap in comparison: the costs for the electricity producing generator amount to less than 3 percent of total costs. Certainly, wind drones will need more and better sensors, processors and other control components, but these cost much less than the saved materials.


How can a wind drone save half the costs of a wind turbine? It is all about physics. A basic construction principle in engineering is to avoid a 90-degree force on an unsupported lever arm wherever possible. Large bridges are therefore supported by arches, columns, or suspension tethers. If parts cannot be supported they have to be made as short as possible.

Wind turbine engineers have done the opposite. Rightfully wanting to build ever larger and more efficient wind turbines they worked to increase the height of the towers and the length of the blades. Both are lever arms in a 90 degree angle to the wind force and they are not supported. Wind engineers would love to tether the tower and the blades. But it is not possible. The wind can blow from all directions, so the rotor has to be able to rotate around the tower and the blades have to spin freely. Nonetheless, wind engineers have excelled in building ever larger wind turbines. They hold the record for building the longest unsupported lever arms in the world. Undoubtedly a great achievement, but one that does not help saving material. The tether of a drone can be 1,000 times lighter than the tower of a turbine simply because it avoids lever arms.


A simple physical fact cuts costs in half. Can other physical facts double the output? Since wind drones are not restricted by lever arms they can fly higher. They easily reach altitudes twice as high as normal wind towers (300 m/1,000 ft. instead of 150 m/500 ft.). Physical facts: on average the wind speed increases with altitude; higher wind speed means more wind power; wind power increases with the cube of the wind speed. Double the wind speed therefore means wind power multiplied by eight (2³).

Altogether these physical facts lead to the conclusion that there is no such thing as a “bad location” for wind drones. Wind drones only know good and excellent wind sites. They will find enough wind at almost any site.

The impact of height differences can easily be illustrated by using wind data of Dresden, Germany (See %%0815-IF-Drone-3%%.12 At the altitude of wind turbines it is a very poor wind location. Not even with the support of the generous German feed-in tariffs does it allow economic energy generation. At wind drone altitude, the wind speed is 60 percent higher (grey columns). This does not sound spectacular, but due to the cubed relationship between wind speed and power the available wind power almost quadruples (blue columns).

At this altitude Dresden becomes an extremely windy place with a wind force only matched by few wind turbine locations such as coasts, mountains or offshore locations. The world’s largest offshore wind park London Array, has a comparable average wind speed of 9.2 m/s at 100-meter hub height.13 The reason is simple. Obstacles on land like forests, hills and buildings slow the wind down. Offshore winds partly owe their strength to the lack of obstacles. The same applies to high altitude winds: no obstacles to slow them down.

In addition, offshore or high altitude winds are steadier and therefore a more reliable source of electricity. Offshore wind turbines run at full capacity more often. Their idle periods per year are much shorter. Their so-called capacity factor is higher. They are therefore better suited to provide base load electricity. On average the output of offshore turbines is twice as high as that of onshore turbines with the same rated capacity.14 But since offshore turbines cost two to three times as much as onshore turbines, the advantage is quickly outweighed. Offshore wind energy is still more costly than onshore wind.15 According to research conducted by E.ON, Germany’s largest utility, offshore wind drones can boost offshore wind turbines’ high yields by another 50 percent. They can run at full capacity 70 percent per annum.16

In summary, wind drones have lower production costs, they can access much stronger high altitude winds and therefore run at full capacity for greater amounts of time. The estimate of many airborne wind energy startups seems realistic: electricity for a quarter of the price of today’s wind energy.

Google shares this belief in the cost-cutting power of wind drones. Google calculated that less than 16 percent of all the onshore U.S. sites are suitable for economic wind energy production with wind turbines. For wind drones this figure more than quadruples. 66 percent of the United States become viable.17

The higher capacity factor does not only lower the price, it also increases quality. The intermittency of most renewable energy sources causes a lot of concerns. Electricity grid operators face the challenge of matching the fluctuating production of renewables with demand. Current scenarios foresee the necessity to invest billions into stronger grids and energy storage. If wind drones can produce with a capacity factor of 70 percent as envisaged by E.ON, they could replace coal, nuclear and gas power plants without the necessity of massive new investments in grid and storage. Grid and distribution costs already make up for the greater part of our electricity bills. The high quality of wind drone power could become a decisive factor, even more important than its low cost.


The first wind drone prototypes are in operation. But when will they be market ready? Soon. Sooner than many other autonomous drones. The reasons: simplicity, safety, and the law.


Various drones have various tasks which vary in difficulty. Wind drones are the ones with the easy job. They fly the same simple pattern, say a circle, over the same space over and over and over again. Conventional wisdom has it that robots and drones will first get into the dull, dirty and dangerous jobs. Sorry, wind drones, we cannot get you dirty and dangerous, but when it comes to dullness it is hard to beat your job.

Flying the same patterns over the same area means that the sensors know exactly what to expect, that the software has to know only a few flight patterns, and that the only variation can come from different weather, namely changes in wind speed and direction. And if the wind drone has to land for inspection or due to extreme weather, the landing site is also always nearby.


No matter how simple a task, something can always go wrong and in case of flying objects the result can be a crash. To be a commercial success, every drone will have to prove that it is safe.
In the beginning wind drones will only be installed in controlled areas in the countryside, or over the sea, where unauthorized access is not allowed. If the public cannot access the flight area, the public cannot be harmed. This is the simplest recipe for safety. Amazon on the other hand might find it difficult to deliver its parcel to your doorstep while keeping a safe distance from people.

Wind drones also have a built-in safety feature that is unique to drones: They are kept constantly on the leash, pardon, tether. So even if all controls go out of control, wind drones can only crash within the area of the tether and will not do any harm outside.

Stationary operation and the strictly defined flight area of wind drones not only increase safety on the ground but also in the air. Wind drone parks can be included in air maps and turned into no-flight zones for low flying air traffic, just as wind parks are today. Air regulators have already honored the additional safety and special features of wind drones. A draft decree of the European airspace authority EASA has an exemption for wind drones (and other drones on the tether) allowing them to fly higher than other drones without the same restrictions.18 And under the new EASA “concept of drone operation”19 the degree of regulation will depend on a specific risk assessment for each use of drones. In case of operation in segregated areas, where drones do not pose a risk to the public, the operator might even approve its own risk assessment. Airspace regulators worldwide are currently working on regulation for drones. They will mostly use comparable flexible concepts, since applying existing strict regulation standards for manned aviation to drones would choke off the respective national drone industry without any safety benefits. So wind drones are not only safer in practice, but this additional safety in the air and on the ground will lead to much lighter regulations. This will make them faster, easier and cheaper to build than other more hazardous and therefore stricter regulated free flying drones or aircraft.

What is true for drones is also true for autonomous cars. Many believe that autonomous cars will become commercial reality in a few years. This is not true. Fully autonomous cars have long ago hit the market. They have been available for purchase since 2008. Where? At your local Caterpillar20 or Komatsu21 dealer, specialized in mining equipment. More and more mines are equipped with fully autonomous haul trucks, which transport rocks and minerals within the mine. Have the engineers at Caterpillar and Komatsu outclassed their counterparts at Google, GM, Tesla, BMW, Volvo, Toyota, Audi, Mercedes by launching their product a decade earlier? Not quite. Haul trucks perform limited and well defined repetitive tasks. They operate stationary in mines, which are controlled distant places with no access for the public. There is little or no regulation on their development and use. The conclusion for drones is obvious.


The strongest argument for wind drones is their potential market: it is huge.

To begin with, the global wind turbine market is a large market. Its volume amounted to $80 billion in 2013.22 Its growth rate averaged 25 percent per year over the last decade23 and the market will continue to grow strongly. But wind drones are not limited to the existing market for wind turbines. A look at the top 20 global companies with the largest revenue as compiled by the Fortune Global 500 list24 illustrates their full market potential:

Energy is big business. But wind energy is still minuscule and accounts for less than 1 percent of total global energy use.25 This will change. And it is mostly a question of competitiveness. Onshore wind turbines are on the brink of becoming competitive with coal and natural gas. This so called grid-parity has been reached in some regions. It means that wind energy is already the cheapest source of electricity even without subsidies. Add wind drones’ potential to slash these costs to one quarter, add steadier production and add their ability to be deployed almost anywhere.

This means that wind drones cannot only compete with wind turbines in their niche but will become the cheapest source of electricity. Cheaper than coal, gas, nuclear and hydro power.

And since electric cars are on the rise, the electricity produced by wind drones will be able to play in the energy major league and compete with oil as a transportation fuel. And oil will have a hard time competing, even at the current “cheap” oil prices. Taking into account the inefficiencies of the combustion engine, oil at $60 per barrel is still a more expensive source of power for a car than the electricity produced by today’s wind turbines. Based on the analysis above, oil would have to sell at a quarter of that price, below $15 per barrel to compete with wind drone energy on a pure cost of fuel basis.

The digital revolution has disrupted many markets, created vast riches and young billionaires. But we have to bear in mind that the digital revolution has only taken place in very limited markets so far. The so-called digital giants Google and Facebook — and many others — are all competing for a share of the online advertising market. This market has a total global volume of $150 billion.26 Compare this to the annual average $2 trillion investment into energy supply required in the next 20 years according to the International Energy Agency.27 Compare this to the $3.4 trillion revenue that the 11 largest energy companies on the Fortune Global 500 list share. Or compare it to the total global energy market that is assumed to have a size of $6 trillion to $10 trillion. This is a difference in market size that could come close to a factor of 100. We cannot imagine what it will look like when the drones the digital revolution created take on the largest market of the world, the energy market.


We have illustrated how the laws of physics in combination with sensors, chips and smart algorithms can replace the tons of steel and concrete wind turbines are made of. This can make wind drone power cheaper than electricity from fossil fuels. Their ability to harvest stronger winds higher up in the air gives wind drones the potential to provide power where it is needed irrespective of the existing wind resource. Cost-effective electricity made by wind drones could even provide the basis for the clean synthetic fuels of the future. And this fuel could be available at less than today’s oil price.

A lack of wind will no longer be a problem. We have seen how the wind resource dramatically increases by doubling the altitude. But this is only the first humble hop of wind drones into the air. Once these altitudes are mastered, it will be tempting to gradually go higher, until they reach the jet stream at 10 km/33,000 ft. Before, many technical and legal problems will have to be solved. But it will be attempted. The wind resources at this altitude are simply too enticing. The median energy density over New York at this height is more than 10 kW/m² 28 of which about 5 kW/m² can be used.29 The total energy consumption per person in the U.S. amounts to 10.5 kW. This includes all electricity use, heating, car and aviation fuels, and even industrial energy consumption.30 This means that harvesting wind in an area of 2m² (22 sq.-ft.) per person, the size of an open front door, could on average provide all our energy. If 10 wind turbines with today’s dimensions were installed in that altitude over New York, they could have the same rated power as an average nuclear power plant, over 1 GW.31 High-altitude wind energy is not only an extremely concentrated source of energy, it is also abundant. It can provide about 100 times of today’s global energy consumption.32 High altitude wind energy could allow us to live a greener lifestyle without the need to reduce our use of energy. For the energy sector this could mean nothing less than finally solving the conflict between economy and ecology.

Burning fossil fuels started the industrial revolution. It enabled the advances of mankind in the last 200 years. Without fossil fuels feeding 7 billion people on this planet would be impossible. But fossil fuels also destroy and pollute nature, poison our cities and homes and cause an ever more dangerous climate change. Furthermore, our reliance on fossil fuels leads to unjustified wealth and power imbalances, to wars over their control and to undemocratic regimes.

When mankind started to burn fossil fuels it made a huge leap forward. When it stops to burn fossil fuels, it will make another big step towards a better world. Drones will help to bring this day much closer than most of us believe today.

3 M. Loyd, Crosswind Kite Power, Journal of Energy, Vol. 4, no. 3, pp. 106-111, 1980
5 Additional Operations & Maintenance costs are 20% of total costs. Source capital costs breakdown: IRENA International Renewable Energy Agency, Working Paper Renewable Energy Technologies: Cost Analysis Series, Volume 1: Power Sector Issue 5/5 Wind Power, June 2012
6 All data is for the MHI Vestas V164-8WM, currently the largest wind turbine prototype of the world.
9 Calculated for 8 MW power and flight altitude of 250 meters. M. Diehl. Airborne Wind Energy, Airborne Wind Energy: Basic Concepts and Physical Foundations. Springer, 2013.
10 A detailed explanation of the higher efficiency of the wind drone wings is beyond the scope of this article. For an introduction to the physics of wind drones see M. Diehl. Airborne Wind Energy, Airborne Wind Energy: Basic Concepts and Physical Foundations. Springer, 2013.
12 ind Data source: Christian Geiss, Technical University Chemnitz, Studies on the vertical wind profile in Saxony (Untersuchungen zum vertikalen Windprofil in Sachsen), 2012
14 A doubling of power output is also roughly expected from average offshore compared to average onshore sites: IRENA International Renewable Energy Agency, Working Paper Renewable Energy Technologies: Cost Analysis Series, Volume 1: Power Sect or Issue 5/5 Wind Power, June 2012
15 IRENA International Renewable Energy Agency, Working Paper Renewable Energy Technologies: Cost Analysis Series, Volume 1: Power Sect or Issue 5/5 Wind Power, June 2012
18 Draft Guidance Material 1 (GM1) Standardized European Rules of the Air SERA.3138(a) paragraph (b) in: NPA 2014-09 .
22 Global Wind Energy Council, Global Wind Report 2013
23 International Energy Agency, World Energy Outlook 2013.
25 0,3% in 2011: Wind 434 TWh, Total Energy Demand: 13.070 Mtoe (= 152,000 TWh), International Energy Agency, World Energy Outlook 2013.
27 International Energy Agency, World Energy Investment Outlook, Executive Summary, 2014,
28 C. Archer, K. Caldeira; Global Assessment of High-Altitude Wind Power, Energies 2009, 2(2), 307-319; doi:10.3390/en20200307,
29 The theoretical maximum is the Betz limit 16/27 or 59%. Modern wind turbines are very close to this with efficiencies of about 50%, including losses in generators, drivetrains etc.
31 The Vestas MHI Vestas V164-8WM with a blade lengt of 82m features a swept area of 21,124 sqm. With 10kW/sqm and 50% efficiency, this results in 105 MW per Turbine or over 1 GW for 10 turbines.
32 K. Marvel et al. Geophysical limits to global wind power, Nature Climate Change, Vol. 2 no. 9 September 9, 2012; M. Jacobson and C. Archer. Saturation wind power potential and its implications for wind energy. Proceedings of the National Academy of Sciences, 2012 (doi:10.1073/pnas.1208993109)

About The Author

Udo Zillmann is the founder and managing partner of Daidalos Capital GmbH, a fund management company that specialized in investing in airborne wind energy companies since 2010 and is currently raising its second special airborne wind energy fund. Mr. Zillmann is author of “Financing Strategies of AWE Companies” in the book “Airborne Wind Energy” (Springer, 2013) and a regular speaker on airborne wind energy. Mr. Zillmann holds degrees in law and business.

Renewable Record for Germany

Germany’s share of renewable energy input into the gross national energy requirement is set to hit the 33% mark for 2015. Some 193 billion kWh will come from solar, wind, and other renewable sources for 2015, around a 20% increase on the previous year, according to the estimates from the Centre for Solar Energy and Hydrogen Research Baden-Württemberg (ZSW) and the German Association of Energy and Water Industries (BDEW).

The most significant increases have been in photovoltaic and wind energy: Wind outlets produced 47% more power up to Oct. 31 than in the same period last year, while photovoltaic sources had already beaten their total production for 2014 in the first 10 months of 2015, despite only modest increases in installations.

“Even if we don’t hit 33%, the overall increase in Germany’s renewable energy share is terrific news,” said Thomas Grigoleit, director of Energy, Environment and Resources at Germany Trade and Invest.

“Not only does it show how important this aspect is in terms of Germany’s Energiewende and climate change targets, it confirms Germany’s pioneering position in the industry. Germany is able not only to install this capacity but integrate it effectively into the grid.”

EPRI says with R&D, coal power can be clean without carbon capture

Carbon capture with underground storage is considered by many to be the best option to reduce carbon dioxide emissions from coal-fired power plants. But development and application of CCS systems face technology, policy and cost challenges.

The Electric Power Research Institute looked at several technologies available or in development that have the potential to enable power plants fueled solely by coal to reduce CO2 emissions through more efficient combustion and use of heat. The results of EPRI’s study have been published in a new white paper, Can Future Coal Power Plants Meet CO2 Emission Standards Without Carbon Capture and Storage?

EPRI’s paper analyzes current and anticipated U.S. and global CO2 emission standards for coal plants, identifies key challenges associated with CCS deployment, and provides detailed descriptions of coal-only technologies that are not ready for commercial deployment but that present opportunities to reduce CO2 emissions.

Today’s most efficient coal-fired plants are the ultra-supercritical plants that produce steam at high temperature (above 593 degrees C or 1,100 degrees F) and emit about 800 kg (1,760 pounds) CO2/MWh. EPRI looked at several technology options for increasing the thermal efficiency of the processes for generating electricity with coal, including:

· Rankine cycles (used by most of today’s coal plants) with higher steam temperatures;
· Combined heat and power applications (also known as cogeneration); and
· Coal gasification integrated with one of four systems — combined cycles (gas turbine plants), supercritical CO2 Brayton cycles (which use the CO2 instead of water or steam as the working fluid), solid oxide fuel cells (SOFCs), and “triple cycles” (a combination of combined cycles and SOFCs).

However, none of the options considered in EPRI’s analysis are currently commercially available, economically viable, and suitable for broad deployment.

National R&D programs in the United States and elsewhere are making progress, but additional public-private R&D investment is needed to accelerate the deployment of many of these technologies.

“It’s critically important for the electric power industry to have as many generation technology and fuel options as possible,” said EPRI Vice President of Generation Tom Alley. “Reducing emissions will be one of the key drivers as the industry makes decisions about existing assets and about the designs and fuels used in the next generation of power plants. EPRI research like this can be invaluable in informing those decisions.”

Waving good buy? A hitherto-obscure piece of physics may be the secret to ocean power generation

THE idea of extracting energy from ocean waves and turning it into electricity is an alluring one. The first serious attempt to do so dates back to 1974, when Stephen Salter of Edinburgh University came up with the idea of “ducks”: house-sized buoys tethered to the sea floor that would convert the swell into rotational motion to drive generators. It failed, as have many subsequent efforts to perform the trick. But the idea of wave power will not go away, and the latest attempt—the brainchild of researchers at Oscilla Power, a firm based in Seattle—is trying to address head-on the reason why previous efforts have foundered.

This reason, according to Rahul Shendure, the firm’s boss, is that those efforts took technologies developed for landlubbers (often as components of wind turbines) and tried to modify them for marine use. The consequence was kit too complicated and sensitive for the rough-and-tumble of life on the ocean waves, and also too vulnerable to corrosion. Better, he reckons, to start from scratch.

Instead of generators with lots of moving parts, Oscilla is developing ones that barely move at all. These employ a little-explored phenomenon called magnetostriction, in which ferromagnetic materials (things like iron, that can be magnetised strongly) change their shape slightly in the presence of a magnetic field. Like many physical processes, this also works in reverse. Apply stresses or strains to such a material and its magnetic characteristics alter. Do this in the presence of permanent magnets and a coil of wire, such as are found in conventional generators, and it will generate electricity.

The core of Oscilla’s design is a bar made from an alloy of iron and aluminium, a mixture that is strongly ferromagnetic. Such bars need be compressed by only one part in 10,000 to have the desired effect. This means, to all intents and purposes, that the generator has no internal moving parts that can go wrong. But compressing a solid metal bar by even this tiny amount requires the application of a huge force. Fortunately, ocean waves are powerful enough to generate this force. Oscilla’s design, as the firm’s name suggests, does it by oscillation.


Its oscillating generators consist of two large objects connected by cables (see diagram). At one end of these cables, floating on the surface, is a buoy that contains the generating apparatus of alloy bars, magnets and coils, together with sets of hydraulic rams which can squeeze the bars as desired. At the cables’ other ends hangs a structure called a heave plate, which is kept stationary by a combination of inertia and the drag of the surrounding water. This arrangement means that, as the buoy rises and falls with the waves at the surface while the heave plate stays more or less put, the tension on the cables increases and decreases. That changing tension drives the rams. The whole system is kept in place by a second set of cables that moor it to the seabed.

A full-scale device, which Oscilla hopes to build by 2018, will be a foam-filled steel buoy 27 metres in diameter, six metres high and weighing 1,000 tonnes, tethered to a toroidal concrete heave plate 70 metres below the surface. It will carry 12 magnetostrictive generators within. Mr Shendure says that a single such buoy, placed a few kilometres offshore, should deliver an average of 600 kilowatts—about the same as an onshore wind turbine. A prototype four metres in diameter underwent a brief but successful open-ocean trial off the Atlantic coast of America last year.

Oscilla’s generators will, Dr Shendure acknowledges, be expensive to build and install. But their simple design, he says, should allow them to operate for decades with no more maintenance than an occasional scrub to remove accumulated barnacles. He calculates that the cost of producing electricity from them will be around ten cents a kilowatt hour. That compares with 16 cents a kilowatt hour for offshore wind farms and six cents for the onshore variety. A grid-connected fossil-fuel power station would be cheaper still—five cents or less. But ten cents represents a decent start for such a novel way of generating electricity.

Electric taxi project in Hong Kong goes belly up: China’s BYD brands 2-year campaign a ‘failure’

Automaker also struggling to sell e-buses in city and has only received orders for 14 so far, it says

Chinese automaker BYD, which is partly owned by Warren Buffett’s Berkshire Hathaway, officially branded its two-year trial run of electric taxis in Hong Kong as a failure on Friday.

“I’m the one to take charge of BYD’s e-taxi project in Hong Kong,” said Ding Haimiao,assistant to the general manager at the carmaker.

“I have to say it’s a failure,” he added.

Ding made the comments to a group of academic and technology industry figures from Hong Kong during a speech in the southern Chinese city of Shenzhen.

In 2013, BYD chairman Wang Chuanfu said he expected the company to launch dozens of e6 electric car taxis in Hong Kong by the end of that year.

He predicted the number would grow to 1,000 by 2014 and 3,000 this year.

That didn’t happen.

BYD has still only launched 45 e6 cabs and three charging stations in Hong Kong – enough to cover 150 electric cabs, it said.

Ding insisted that the firm has proved to the local government that electric cabs can greatly benefit the city by saving energy costs and better protecting the environment

“I’m calling it a failure because we lost so much money from this project,” he said.

The automaker has made a series of investments to support this programme, for example covering the cost of charging stations and vehicle maintenance, he added.



He said the model fits the local market but has nonetheless met with resistance from a number of industry figures, especially established taxi drivers.

“The Hong Kong government already knows [all] the figures and results, like the energy cost savings. But it really depends on the government [to see] how far it will go in moving forward this e-taxi plan,” he said.

It is normal for new policies from the government to inspire a backlash until doubts are cleared up, he said.

READ MORE: ‘Our business is tough enough’: Plan to launch premium taxi service in Hong Kong raises hackles [3]

In another part of its electric push, BYD has also made slow progress in pressing ahead with electric buses in Hong Kong, Ding said.

The company has so far received orders for 14 of these in Hong Kong, but the number of orders pales compared to other traffic-heavy markets in which it operates, he added.

BYD said last week it plans to sell 15,000 electric taxis and 6,000 electric buses this year.

Analysts say 95 per cent of these are likely destined for China.

In April, the company won an order from the state of California to deliver 60 electric buses.